Re: [PATCH v14 03/11] tests: Add test for QAPI builtin type time

[Tao Xu <tao3.xu@intel.com>]

On 11/7/2019 4:53 AM, Eduardo Habkost wrote:
> On Mon, Oct 28, 2019 at 03:52:12PM +0800, Tao Xu wrote:
>> Add tests for time input such as zero, around limit of precision,
>> signed upper limit, actual upper limit, beyond limits, time suffixes,
>> and etc.
>>
>> Signed-off-by: Tao Xu <tao3.xu@intel.com>
>> ---
> [...]
>> +    /* Close to signed upper limit 0x7ffffffffffffc00 (53 msbs set) */
>> +    qdict = keyval_parse("time1=9223372036854774784," /* 7ffffffffffffc00 */
>> +                         "time2=9223372036854775295", /* 7ffffffffffffdff */
>> +                         NULL, &error_abort);
>> +    v = qobject_input_visitor_new_keyval(QOBJECT(qdict));
>> +    qobject_unref(qdict);
>> +    visit_start_struct(v, NULL, NULL, 0, &error_abort);
>> +    visit_type_time(v, "time1", &time, &error_abort);
>> +    g_assert_cmphex(time, ==, 0x7ffffffffffffc00);
>> +    visit_type_time(v, "time2", &time, &error_abort);
>> +    g_assert_cmphex(time, ==, 0x7ffffffffffffc00);
> 
> I'm confused by this test case and the one below[1].  Are these
> known bugs?  Shouldn't we document them as known bugs?

Because do_strtosz() or do_strtomul() actually parse with strtod(), so 
the precision is 53 bits, so in these cases, 7ffffffffffffdff and 
fffffffffffffbff are rounded.
> 
>> +    visit_check_struct(v, &error_abort);
>> +    visit_end_struct(v, NULL);
>> +    visit_free(v);
>> +
>> +    /* Close to actual upper limit 0xfffffffffffff800 (53 msbs set) */
>> +    qdict = keyval_parse("time1=18446744073709549568," /* fffffffffffff800 */
>> +                         "time2=18446744073709550591", /* fffffffffffffbff */
>> +                         NULL, &error_abort);
>> +    v = qobject_input_visitor_new_keyval(QOBJECT(qdict));
>> +    qobject_unref(qdict);
>> +    visit_start_struct(v, NULL, NULL, 0, &error_abort);
>> +    visit_type_time(v, "time1", &time, &error_abort);
>> +    g_assert_cmphex(time, ==, 0xfffffffffffff800);
>> +    visit_type_time(v, "time2", &time, &error_abort);
>> +    g_assert_cmphex(time, ==, 0xfffffffffffff800);
> 
> [1]
> 
>> +    visit_check_struct(v, &error_abort);
>> +    visit_end_struct(v, NULL);
>> +    visit_free(v);
> [...]
>